[OPTICAL REVIEW Vol. 3, No. 2 (1996) 71-82]

Enhancement Factor in the Light Backscattered by Fractal Aggregated Media

Aristide DOGARIU,*[footnote] Jun UOZUMI and Toshimitsu ASAKURA

Research Institute for Electronic Science, Hokkaido University, Sapporo, 060 Japan

(Received September 21, 1995; Accepted January 24, 1996)

We investigate the phenomenon of the enhanced backscattering of light from soft sediments of fractal clusters. The clusters consist of spherical PMMA particles with the diameter of 0.4μm, aggregated in aqueous solutions of NaCl. We found that the kinetics of aggregation, which determines the average cluster size in sediments, is controlled by the salt concentration and that the sediments are mutually self-similar media. In comparison to uniform random media, specific features for the enhancement peaks are revealed. It is found that the peak line-shape reflects the particularities of the density of scatterers in a fractal-like medium. It is shown experimentally that the enhancement factor in the light backscattered by fractal aggregated media is sensitive to the average cluster size. On this basis, we suggest a possible way to distinguish between mutually self-similar media.

Key words : enhanced backscattering, fractal cluster, aggregated particles, mutually self-similar media, cluster size, enhancement factor

*Present address: Center for Research and Education in Optics and Lasers, University of Central Florida, Orlando, Florida 32826, USA.